All criminal charges will move forward against the conductor of an Amtrak train that derailed in 2015, a judge ruled Tuesday, according to an official in the Pennsylvania Attorney General's office. The 2015 crash killed eight people and injured 100.

By Ellie Kaufman and Lauren del Valle CNN

(CNN) -- All criminal charges will move forward against the conductor of an Amtrak train that derailed in 2015, a judge ruled Tuesday, according to an official in the Pennsylvania Attorney General's office. The 2015 crash killed eight people and injured 100.

A Philadelphia Court of Common Pleas judge overturned a previous lower court ruling that had dismissed charges against Brandon Bostian, the engineer.

Attorney General Josh Shapiro appealed that decision in October. On Tuesday, Judge Kathryn Lewis decided to overturn the lower court's decision and move forward with the charges.

"We're pleased with the court's ruling today," Shapiro said in a statement. "This is an important step in the legal process of this case. We will seek justice for every victim of the Amtrak train crash."

Thomas R. Kline, an attorney who represents John Jacobs, the father of Rachel Jacobs who died in the crash, filed the initial criminal complaint that led Bostian to this moment.

"This is an important step forward towards justice for the families," Kline told CNN. "This has been a long road from the denial by the local county prosecutor through two judges to the trial level court where a ruling today assured that Brandon Bostian will stand trial."

Bostian's attorney did not respond to CNN's request for comment.

Charges dropped, then reinstated

After the National Transportation Safety Board completed an investigation into the crash, local prosecutors decided not to press charges against Bostian. The NTSB investigation concluded that, while Bostian did cause the accident for operating the train "far in excess of the speed limit," there was no evidence he acted with criminal "intent" or criminal "knowledge." The train was traveling at 160 miles per hour around a sharp curve that had a speed limit of 50 miles per hour.

But Pennsylvania law allows citizens to file private criminal complaints. Two days after the Philadelphia District Attorney's office announced it would not press charges, Kline filed the private criminal complaint. The complaint included eight counts of involuntary manslaughter and numerous charges of reckless endangerment.

After Kline filed his complaint, prosecutors sent the charges to the Pennsylvania Attorney General. The Attorney General added causing or risking a catastrophe, a felony charge, to the complaint.

Kline and attorney Robert Mongeluzzi represent 32 victims in ongoing litigation against Amtrak.

NTSB inquiry results

The 2016 NTSB investigation into the derailment concluded that, prior to the crash, Bostian was distracted by radio conversations between other trains and dispatchers about other trains being hit with projectiles.

NTSB investigators say they found no evidence that the Amtrak engineer was using alcohol, drugs or a cell phone. The ride from the train station in Philadelphia to the site of the derailment was 11 minutes. Investigators say that during seven to nine of those minutes, the engineer was listening to and participating in the radio conversations regarding other trains being hit with a projectile.

When NTSB investigators interviewed him, the discussion of trains being hit by a projectile was one of the few details the engineer remembered clearly.

The section of track where the train derailed was not equipped with safety equipment called automatic train control. The automated system notifies an engineer if the train is speeding and applies the brakes automatically if the engineer does not respond. The NTSB has said had that equipment been installed the accident would not have happened.

Amtrak has since installed that speed control along the section of track where the derailment occurred.